Apparatus for separating solids of different gravities



June 23, 1942. F. PARDEE 2,287,748

APPARATUS FOR SEPARATING SOLID OF DIFFERENT GRAVITIES Filed Feb. 25, 1941 2 Sheets-Sheet l INVENTOR. 1 RA NKJDA RD 55 -A TTORNEY June 23-, 1942. PARD E 2,287,748"

APPARATUS FOR SEPARAT ING SOLIDS OF DIFFERENT GRAVITIES Filed Feb. 25, 1941 2 Sheets-Sheet 2 'INVENTOR. [Z24 /w( El E0 E5 Patented June 23, 1942 3 'l APPARATUS FOR SEPARATING SOLIDS OF DIFFERENT GRAVITIES Frank Pardee, Hazleton, Pa., assignor to Anthrae cite Separator Company,

Hazleton, Pa., a cor-.

poration of Pennsylvania Application February 25, 1941, Serial No. 380,470 6 Claims. (01. 209-456) My present invention relates to improvements in apparatus for separating solids of different densities as, for example, separating slate and refuse from coal.

This invention is an improvement on the apparatus of my patents, Nos. 2,199,091 of April 30, 1940 and 2,205,432 of June 25, 1940.

In the invention of said patents, a mixture of solids, such as coal and slate or refuse, is distributed onto a supporting and separating plate through which a buoying fluid is passed to buoy the solids upwardly and then permit them to settle in such a manner that the heavier material which settles more rapidly sinks to the plate substantially free from the lighter material which is then scrapedto one side by a mechan-:

ical scraper while the lighter material thus freed from the heavier material is swept in the opposite direction and thus'separated from the heavier material, such as slateor rock.

In the specific embodiments of said patents the invention was illustrated by the use of a perforated conical plate through which the buoying fluid was intermittently forced upwardly and over which a scraper having a spirally arranged blade was rotatedin such manner as to force or push the material immediately adjacent the plate toward the upper part of theplate while the lighter material was buoyed over the upper edge of the scraper to the lower part of the plate. Thus the lighter material passed in one direction from the point or zone of distribution of the mixed material and the heavier material was pushed in the opposite direction.

In my present invention the capacity of the apparatus to separate the material is increased. For this purpose I provide a scraper having an undulating or sinuous upper edge or otherwise arranged to have alternating greater and lesser height. The scraper or scrapers are arranged spirally on the supporting plate onto which the mixed material is delivered and rotate about a central axis so that at any particular radius of the conical plate the scraper wall moves both upwardly and sidewise or in a rotational direction thus bringing alternately: higher and lower parts of the wall past each radius of the plate.

Consequently, when a buoying fluid passes upwardly through the supporting plate it lifts and deposits lower strata of heavier material and upper strata of lighter material up to the full height of the scraper. With progressive movement of the scraper the higher strata, faced or supported by the higher parts of the scraper,

will at the next pulsation be adjacent a lower part of the scraper wall and accordingly the lighter upper stratum will readily be swept over thelower heightof the scraper wall. According- I ly, the scraper having the undulating upper edge provides areas'which permit the formation of deeper strata of the separated materials followed by a period in which the scraper height is lower and the buoying surge of fluid downwardly over the plate is increased rapidly to remove the separated upper stratum.

The various features of my invention are illustrated by way of example in the accompanying drawings in which: Fig. 1 is a vertical section of separating apparatus embodying a preferred form of'the invention. Fig. 2 is a plan view of the apparatus shown in Fig. 1. Fig. 3 is a sectional elevation similar to that of Fig. 1 but taken at a right angle thereto and on a larger scale. Fig. 4 is a detail vertical section; Fig. 5 a plan view showing the action of the scraper and Fig. 6 is a vertical section on a larger scale than that of Fig. 3 showing the action of the buoying fluid in connection with the scraper.

Referring more particularly to Figs. 1, 2 and 3 of the accompanying drawings, the invention is illustrated as applied to a separating apparatus in which the mixed material, such as coal and slate, is fed and distributed from a supply hopper or bin l0 below an annular feed plate I I to a perforated supporting plate l2 of conical curvature and is received on said plate in a zone between a central opening l3 and the outer edge M of the plate. Buoying fluid is forced intermittently upwardly through openings l5 in the plate, Figs. 4 and 6, and then flows over the lower edge l4 into an annular receiving trough It. The fluid may be circulated by any suitable mechanism as, for example, by the annular piston plate I! reciprocated vertically in the cham' ber l8 below the plate l2, by means of a head I9 and a tilting lever or walking beam 29. With each upward stroke of the piston plate I! liquid is forced upwardly through the plate l2, thence flows outwardly and downwardly into the receiving channel '16 and through a check valve 2| into the space below the piston plate ll. With the downward movement of the piston plate I! the fluid-is trapped by the check valve 2| and flows upwardly through a check valve 22 on the piston plate I! into the space above the piston plate to be again circulated in the next upward movement of the piston plate I1 and head l9. Other means for intermittent circulation of the fluid may be used and the above is merely given as a convenient and preferred means for this purpose.

As the fluid flows upwardly through the openings of the plate l2 it buoys upwardly the material or mixture of materials that had been de- 5 posited on the plate, lifting the lighter material more readily than the heavier material. Thereafter the heavier material settles more rapidly, thus separating to a lower stratum, while the lighter material then settles onto this lower stratum as an upper stratum of lighter material.

The outward movement of the buoying fluid over the plate into the trough It also tends to carry the material downwardly and outwardly with it. This buoying of the material to the outer edge of the plate is restrained by spirally arranged scrapers of which two scrapers 23 and 24 are shown in the accompanying drawings.

The stratum of material settling after each upward surge of the buoying fluid deposits on the plate extending upwardly from the scrapers until it attains the height of, the scraper as indicated in Fig. 6. The scrapers 23 and 24 have an undulating or sinuous upper edge as shown 5 particularly in Figs. 3, 4 and 6 and are supported bysupporting rods 25 from the arms 26 mounted on a rotating vertical shaft 21 so that the scrapers are rotated about the axis of the shaft 21. 30

As the material settles it will, therefore, build up against the face of the scrapers at different levels corresponding to the varying height of the scraper. As the shaft 21 and arms 26 rotate the scrapers move relatively sidewise so that with the next upward and outward surge of the bu0y-' ing fluid the material that has deposited behind the higher parts of the scrapers will now be hacked or faced by a lower part and can thus be readily swept over this relatively lower edge of the scraper.

Accordingly, the material first builds a deposit behind the higher parts of the scraper, indicated at 21 in Fig. 4, and then upon the shifting of the scraper these higher deposits are swept over the succeeding lower edges, indicated at 29 in Fig. 4. Inasmuch as only the upper part of the deposit is thus swept over the scraper and downwardly, it is relatively free from the heavier material, such as slate. Therefore, the material to be separated may be fed more rapidly to the plate and more rapidly separated into the heavier and lighter parts and the capacity of the apparatus thereby greatly increased.

The capacity may be still further increased by having some of the scrapers higher than others, as indicated by way of example in Fig. 6 where the scraper 23 is of a lower average height than the scraper 24, or may be lower in a certain part of its length and possibly higher in the remainso ing part to facilitate the downward buoying of material that has but a very little of the heavier material or, otherwise expressed, a very shallow lower stratum.

The lighter material is thus swept over the outer edge of the plate and received on a perforated supporting plate 23 in the annular channel M on which it is scraped by hoes 29 attached to the outer ends of the arms 26 by means of brackets 30 so as to drag or sweep the separated coal into a chute 3| and thence into a conveyor 32. The separated slate or heavier material drops through the central opening or passage l3 onto a chute 33 and thence to a refuse pile.

Through the above invention it will, therefore,

be apparent that a relatively thick layer of lighter material is deposited substantially free from the heavier material to a relatively great depth behind a part of the scraper that is temporarily of greater height but which is then replaced by a part of the scraper of lower height over which the relatively deep stratum of lighter material may be easily and quickly buoyed so that it is easily and quickly removed upon being freed from the heavier slate or refuse. Also by providing scrapers of different heights at different parts of the apparatus, the downward or outward flow of the lighter material is facilitated when it is substantially freed from the heavier material or slate, or when the latter material such as slate forms a relatively thin lower stratum.

Having described my invention, what I claim 1. Apparatus for separating solids of different densities which comprises a supporting conical perforated separating plate, means for buoying fluid through said plate and over the lower edge thereof, means to deposit materials to be separated in an annular zone between said upper and lower edges, a scraper to move said material t0- ward the upper part of said plate, said scraper having an undulating upper edge to provide areas that permit formation of deeper strata of the separated materials followed by periods where the scraper height is lower and the buoying surge of the fluid downwardly over the plate is increased rapidly to remove the separated upper stratum.

2. Apparatus for separating solids of different densities which comprises a perforated conical plate, means for forcing a buoying fluid upwardly through said plate and toward the lower edge thereof, means to feed mixtures of materials to be separated in an annular zone between the upper and lower edges of said plate, spiral scrapers on said plate and means to rotate said scrapers in a direction to scrape material upwardly on said plate, said scrapers having undulated upper edges to provide areas that permit formation of deeper strata of the separated materials followed by periods where the scraper height is lower and the buoying surge of the fluid downwardly over the plate is increased rapidly to remove the separated upper stratum.

3. Apparatus for separating solids of different densities which comprises a perforated conical plate, means for forcing a buoying fluid upwardly through said plate and toward the lower edge thereof, means to feed mixtures of materials to be separated in an annular zone between the upper and lower edges of said plate, spiral scrapers on said plate and means to rotate said scrapers in a direction to scrape material' upwardly on said plate, said scrapers having undulating upper edges to provide areas that permit formation of deeper strata of the separated materials followed by periods where the scraper height is lower and the buoying surge of the fluid downwardly over the plate is increased rapidly to remove the separated upper stratum, the average height of one of said scrapers being less than the average height of the adjacent portion of the other of said scrapers.

4. Apparatus for separating solids of different densities which comprises a supporting plate through and over which a buoying fluid may pass to buoy lighter material upwardly and toward one direction on said plate, means to pass buoying fluid upwardly through and over an edge of said plate and a scraper inclined to said direction to move heavier material in the opposite directionon said plate when moved transversely of said direction of flow and means to move said scraper in a direction transverse to the direction of movement of said lighter material, said scraper having an undulating upper edge to provide areas that permit formation of deeper strata of the separated materials followed by periods where the scraper height is lowered and the buoying surge of the fluid downwardly over the plate is increased rapidly to remove the separated upper stratum.

5. Apparatus for separating solids of different densities which comprises an inclined supporting plate through and over which a buoying fluid may pass to buoy lighter material upwardly and toward the downward edge of said plate, means to pass buoyin-g fluid upwardly through and over an edge of said plate, a scraper to move the heavier material on said plate in the opposite direction, said scraper having a movement transverse to the inclination of said plate and being inclined to said movement and having an undulating upper edge to provide areas that permit formation of deeper strata of the separated materials followed by periods where the scraper height is lowered and the buoying surge of the fluid downwardly over the plate is increased rapidly to remove the separated upper stratum.

6. Apparatus for separating solids of diiferent densities which comprises a conical supporting plate through and over which a buoying fluid may pass to buoy lighter material upwardly toward the lower edge of said plate, means to circulate a buoying fluid upwardly through said plate and outwardly over the edge thereof and a rotating spiral scraper on said plate rotatable in a direction to move heavier material upwardly on said plate, said scraper having an undulating upper edge to provide areas that permit formation of deeper strata of the separated materials followed by periods where the scraper height is lowered and the buoying surge of the fluid downwardly over the plate is increased rapidly to remove the separated upper stratum.

FRANK PARDEE. 

